Processing kodak motion picture films, module 3 analytical procedures

Extraction of AF No. 9
1. Add, from a tip-up pipet, 20 mL of 2 N acetic acid to
separatory funnel No. 3.
2. Stopper the funnel and begin mixing gently; vent
through the stopper, very frequently until gas
evolution ceases.
3. When gas evolution stops, remove the stopper and
flush the remaining carbon dioxide out of the
separatory funnel with a gentle stream of air or
nitrogen. (Do not bubble through the solution in the
separatory funnel.)
4. Pipet (wipe) 40.0 mL of 4-methyl-2-pentanone into
the separatory funnel.
5. Stopper and shake the funnel for 30 seconds.
6. Allow the layers to separate; swirl the funnel, then
discard the lower (aqueous) layer.
Drying the 4-methyl-2-pentanone
1. Weigh 25 grams of anhydrous sodium sulfate to the
nearest gram.
2. Drain and discard about 1 mL of the 4-methyl-
2pentanone to flush the water out of the stem of the
separatory funnel No. 3.
3. Drain the 4-methyl-2-pentanone into a 150-mL beaker
containing a magnetic stir bar.
4. Place the beaker on a magnetic mixer and begin
stirring without splashing.
5. Add, while stirring, the 25 grams of sodium sulfate;
continue stirring for 1 minute.
Dye Formation
Note: Water destroys the dye. The volumetric flask must be
dry.
1. Pipet (wipe) 25.0 mL of sodium methoxide in
methanol reagent into a clean dry 50-mL volumetric
flask.
2. Fill the flask to volume with the 4-methyl-2-pentanone
containing AF No. 9.
Note: If necessary stir the sodium sulfate with a glass
stirring rod to free more of the 4-methyl2-pentanone.
3. Immediately start a timer for 8 minutes; stopper and
invert the flask to mix.
a. If the solution is even slightly turbid after mixing,
the results will be high. See Introduction.
b. If the laboratory temperature is below 21°C, place
the volumetric flask in a 27°C constanttemperature
bath for most of the 8-minute reaction
time. For more information, see the
INTRODUCTION.
Absorbance Measurement
1. Rinse, at least twice, a clean glass-stoppered 1-cm
silica cell with methanol.
2. With the contents of the volumetric flask, rinse twice.
then fill the cell; stopper the cell.
3. When the alarm sounds, measure the absorbance at
550 nm against air on a spectrophotometer (A550 ).
Note:
a. During the 8-minute wait, the sample should not
be warmed (or chilled) by unnecessary handling
or by storing in a warm (or cold) place.
b. The cell should not be placed in the
spectrophotometer for more than a minute before
reading.
Calculation:
EASTMAN Anti-Fog No. 9, g/L = 0.547(A 550) + 0.06
2 Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03